1. Field of the Invention
The present invention relates to a photosensitive resin composition, which is applicable to formation of a pattern for a semiconductor device such as a printed wiring board, VLSI or the like, for example.
2. Description of the Background Art
A pattern for a semiconductor element, a printed wiring board or the like is currently formed by photolithography. Such a pattern is formed through a resist material, which is exposed by an active beam such as a radiation beam. In general, such a resist material has been prepared from a compound which is decomposed or cured by radiation exposure. However, since such a general compound consecutively reacts upon radiation exposure, it has been impossible to greatly increase sensitivity of the resin material.
In order to solve such a problem, new resist materials have recently been studied in consideration of a chemically amplified mechanism. For example, a report by Hiroshi Ito, Proc. SPIE, Vol. 920, pp. 33-41 (1988) discloses such a chemically amplified resist material. This resist material contains the compound which generates an acid catalyst upon radiation exposure and heat treatment is performed to facilitate reaction. Since the radiation may be applied in a quantity for generating the acid by an amount for serving as a catalyst, it is possible to obtain an extremely sensitive resist material.
In such a method, however, available materials for the catalyst are restricted since the acid is generated by radiation exposure. In the system of generating an acid through radiation exposure, further, active species of protons are extremely small. Therefore, the reaction is diffused in places other than the region ensured by the heat treatment, to problematically reduce the resolution.
When the conventional resist material is applied to a printed board, the acid generated by light exposure inevitably corrodes copper wires which are provided on the board. Thus, it has been problematic to employ a resist material which is prepared by a decomposition reaction mechanism with an acid catalyst.
Mark R. Winkle et al., J. Photopolym. Sci. Technal, Vol. 3, pp. 419-422 (1990) discloses a resist material prepared by using a photobase generator which generates a base upon radiation exposure. According to the method disclosed in this literature, an acid is neutralized by a base which is generated upon light exposure to induce reaction in portions other than that exposed to the light, thereby forming a pattern. In the reaction-induced portions, therefore, reaction takes place through the acid serving as a catalyst, to cause a problem which is similar to that of the case employing the acid catalyst.